celluloid

nouns

highly flammable substance made from cellulose nitrate and camphor; used in e.g. motion-picture and X-ray film; its use has decreased with the development of nonflammable thermoplastics
is a type of (narrower)
a material that softens when heated and hardens again when cooled
a medium that disseminates moving pictures
"theater pieces transferred to celluloid"; "this story would be good cinema"; "film coverage of sporting events"

adjectives

artificial as if portrayed in a film
"a novel with flat celluloid characters"